Dual stimulation of Epstein-Barr Virus (EBV)-specific CD4+- and CD8+-T-cell responses by a chimeric antigen construct: potential therapeutic vaccine for EBV-positive nasopharyngeal carcinoma

J Virol. 2004 Jan;78(2):768-78. doi: 10.1128/jvi.78.2.768-778.2004.

Abstract

Virus-associated malignancies are potential targets for immunotherapeutic vaccines aiming to stimulate T-cell responses against viral antigens expressed in tumor cells. Epstein-Barr virus (EBV)-associated nasopharyngeal carcinoma, a high-incidence tumor in southern China, expresses a limited set of EBV proteins, including the nuclear antigen EBNA1, an abundant source of HLA class II-restricted CD4(+) T-cell epitopes, and the latent membrane protein LMP2, a source of subdominant CD8(+) T-cell epitopes presented by HLA class I alleles common in the Chinese population. We used appropriately modified gene sequences from a Chinese EBV strain to generate a modified vaccinia virus Ankara recombinant, MVA-EL, expressing the CD4 epitope-rich C-terminal domain of EBNA1 fused to full-length LMP2. The endogenously expressed fusion protein EL is efficiently processed via the HLA class I pathway, and MVA-EL-infected dendritic cells selectively reactivate LMP2-specific CD8(+) memory T-cell responses from immune donors in vitro. Surprisingly, endogenously expressed EL also directly accesses the HLA class II presentation pathway and, unlike endogenously expressed EBNA1 itself, efficiently reactivates CD4(+) memory T-cell responses in vitro. This unscheduled access to the HLA class II pathway is coincident with EL-mediated redirection of the EBNA1 domain from its native nuclear location to dense cytoplasmic patches. Given its immunogenicity to both CD4(+) and CD8(+) T cells, MVA-EL has potential as a therapeutic vaccine in the context of nasopharyngeal carcinoma.

MeSH terms

  • CD4-Positive T-Lymphocytes / immunology
  • CD8-Positive T-Lymphocytes / immunology
  • Carcinoma / immunology*
  • Carcinoma / prevention & control
  • Carcinoma / virology
  • Cell Line
  • Epstein-Barr Virus Infections / immunology
  • Epstein-Barr Virus Infections / prevention & control
  • Epstein-Barr Virus Nuclear Antigens / genetics
  • Epstein-Barr Virus Nuclear Antigens / immunology*
  • Epstein-Barr Virus Nuclear Antigens / metabolism
  • Genetic Vectors
  • HeLa Cells
  • Herpesvirus 4, Human / immunology*
  • Humans
  • Lymphocyte Activation / immunology
  • Nasopharyngeal Neoplasms / immunology*
  • Nasopharyngeal Neoplasms / prevention & control
  • Nasopharyngeal Neoplasms / virology
  • Recombinant Fusion Proteins / genetics
  • Recombinant Fusion Proteins / immunology
  • Recombinant Fusion Proteins / metabolism
  • Vaccinia virus / genetics
  • Viral Matrix Proteins / genetics
  • Viral Matrix Proteins / immunology*
  • Viral Matrix Proteins / metabolism
  • Viral Vaccines / genetics
  • Viral Vaccines / immunology*

Substances

  • EBV-associated membrane antigen, Epstein-Barr virus
  • Epstein-Barr Virus Nuclear Antigens
  • Recombinant Fusion Proteins
  • Viral Matrix Proteins
  • Viral Vaccines
  • EBV-encoded nuclear antigen 1